Device and method

ABSTRACT

A device includes circuitry that dynamically changes an uplink/downlink configuration of a time division duplex (TDD) carrier. The circuitry notifies a terminal device of a radio resource for device-to-device communication appropriate for the uplink/downlink configuration. The radio resource is a radio resource of at least one uplink subframe of the uplink/downlink configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2014-153812 filed Jul. 29, 2014, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a device and a method.

BACKGROUND ART

Device-to-device communication (D2D communication) is communication inwhich two or more terminal devices transmit and receive signalsdirectly, unlike typical cellular communication in which a base stationand a terminal device transmit and receive signals. For this reason, itis anticipated that D2D communication will be used to create new usagescenarios for terminal devices that differ from the typical cellularcommunication above. For example, various applications are conceivable,such as information sharing by data communication between nearbyterminal devices or among a group of nearby terminal devices,distribution of information from an installed terminal device, andautonomous communication between machines, called machine-to-machine(M2M) communication.

Additionally, it is conceivable that D2D communication will be put toeffective use in data offloading in response to the significant increasein data traffic due to the recent increase in smartphones. For example,in recent years, there has been a sharp rise in the necessity totransmit and receive video image streaming data. However, since videoimages typically have large data sizes, there is a problem of consumingmany resources on a radio access network (RAN). Consequently, ifterminal devices are in a state suitable for D2D communication with eachother, such as when the terminal devices are a short distance away fromeach other, video image data may be offloaded to D2D communication,thereby moderating the resource consumption and processing load on aRAN. In this way, D2D communication provides value to bothtelecommunications carriers and users. For this reason, D2Dcommunication is currently recognized as one crucial technology area forLong Term Evolution (LTE), and is receiving attention from the 3rdGeneration Partnership Project (3GPP) standards committee.

For example, Non Patent Literature 1 discloses a case in which D2Dcommunication is performed in an uplink subframe within a networkcoverage area in the case of time division duplex (TDD).

CITATION LIST Non Patent Literature

-   [NPL 1] 3GPP TR 36.843 V12.0.0 (March 2014)

SUMMARY Technical Problem

For example, as radio resources available for D2D communication,periodic radio resources are allocated. For example, at periods of aninteger multiple of a radio frame, radio resources of a specificsubframe are allocated as the radio resources available for D2Dcommunication. Therefore, D2D communication is performed in the specificsubframe.

For example, when D2D communication is performed in a TDD carrier, radioresources of an uplink subframe of an uplink/downlink configuration(UL/DL configuration) of the TDD carrier are allocated as the radioresources available for D2D communication within a network coveragearea. Therefore, D2D communication is performed in the uplink subframe.

However, when the UL/DL configuration of the TDD carrier is dynamicallychanged, the uplink subframe in which D2D communication is performed maybe changed to a downlink subframe or a special subframe. As a result,D2D communication may be performed in the downlink subframe or thespecial subframe. That is, D2D communication that does not comply withcellular communication standards may be performed.

Accordingly, it is preferable to provide a mechanism in which a terminaldevice can appropriately perform D2D communication under a TDDenvironment.

Solution to Problem

According to an embodiment of the present disclosure, there is provideda device including: circuitry configured to dynamically change anuplink/downlink configuration of a time division duplex (TDD) carrier.The circuitry notifies a terminal device of a radio resource fordevice-to-device communication for the uplink/downlink configuration.The radio resource is a radio resource of at least one uplink subframeof the uplink/downlink configuration.

According to another embodiment of the present disclosure, there isprovided a method including: dynamically changing, by a processor, anuplink/downlink configuration of a time division duplex (TDD) carrier;and notifying a terminal device of a radio resource for device-to-devicecommunication for the uplink/downlink configuration. The radio resourceis a radio resource of at least one uplink subframe of theuplink/downlink configuration.

According to another embodiment of the present disclosure, there isprovided a device including: circuitry configured to acquire informationindicating a radio resource for device-to-device communication for anuplink/downlink configuration of a TDD carrier that is dynamicallychanged by a base station; and the circuitry is further configured tocontrol device-to-device communication using the radio resource. Theradio resource is a radio resource of at least one uplink subframe ofthe uplink/downlink configuration.

According to another embodiment of the present disclosure, there isprovided a method including: acquiring information indicating a radioresource for device-to-device communication for an uplink/downlinkconfiguration of a time division duplex (TDD) carrier that isdynamically changed by a base station; and controlling, by a processor,device-to-device communication using the radio resource. The radioresource is a radio resource of at least one uplink subframe of theuplink/downlink configuration.

Advantageous Effects of Invention

According to one or more of embodiments of the present disclosuredescribed above, a terminal device can appropriately perform D2Dcommunication under a TDD environment, but the present disclosure is notnecessarily limited to this effect. Along with or instead of thiseffect, any effect shown in this specification or other effects that maybe understood from this specification may be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a first explanatory diagram illustrating a specific example ofa use case of D2D communication.

FIG. 2 is a second explanatory diagram illustrating a specific exampleof a use case of D2D communication.

FIG. 3 is an explanatory diagram illustrating exemplary timings of a PSSand an SSS in FDD.

FIG. 4 is an explanatory diagram illustrating exemplary timings of a PSSand an SSS in TDD.

FIG. 5 is an explanatory diagram illustrating a radio frame andsubframes in a cellular system.

FIG. 6 is an explanatory diagram illustrating an exemplary resourcepool.

FIG. 7 is an explanatory diagram illustrating an example of a signal andinformation transmitted in a resource pool.

FIG. 8 is an explanatory diagram illustrating a UL/DL configuration.

FIG. 9 is an explanatory diagram schematically illustrating an exemplaryconfiguration of a communication system according to an embodiment ofthe present disclosure.

FIG. 10 is a block diagram illustrating an exemplary configuration of abase station according to the embodiment.

FIG. 11 is a block diagram illustrating an exemplary configuration of aterminal device according to the embodiment.

FIG. 12 is an explanatory diagram illustrating a first example of D2Dresources.

FIG. 13 is an explanatory diagram illustrating a notification example ofD2D resources according to a change of a UL/DL configuration.

FIG. 14 is an explanatory diagram illustrating a second example of D2Dresources.

FIG. 15 is an explanatory diagram illustrating a third example of D2Dresources.

FIG. 16 is an explanatory diagram illustrating a fourth example of D2Dresources.

FIG. 17 is an explanatory diagram illustrating a fifth example of D2Dresources.

FIG. 18 is an explanatory diagram illustrating a first example of aperiod for each configuration.

FIG. 19 is an explanatory diagram illustrating a second example of aperiod for each configuration.

FIG. 20 is a sequence diagram schematically illustrating a first exampleof a process flow according to the embodiment.

FIG. 21 is a sequence diagram schematically illustrating a secondexample of a process flow according to the embodiment.

FIG. 22 is a sequence diagram schematically illustrating a third exampleof a process flow according to the embodiment of the present disclosure.

FIG. 23 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 24 is a block diagram illustrating a second example of a schematicconfiguration of an eNB.

FIG. 25 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 26 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Also, in this specification and the appended drawings, elements havingsubstantially the same function and structure may in some cases bedistinguished by different letters appended to the same sign. Forexample, multiple elements having substantially the same function andstructure are distinguished as terminal devices 10A, 10B, 10C, and so onas appropriate. On the other hand, when not particularly distinguishingeach of multiple elements having substantially the same function andstructure, only the same sign will be given. For example, the terminaldevices 10A, 10B, 10C will be simply designated the terminal device 10when not being particularly distinguished.

Hereinafter, the description will proceed in the following order.

1. Introduction

2. Technical problems according to embodiments of present disclosure

3. Schematic configuration of communication system

4. Configuration of respective devices

4.1. Base station configuration

4.2. Terminal device configuration

5. Technical features according to embodiments of present disclosure

5.1. First technical features

5.2. Second technical features

5.3. Other technical features

6. Process flow

7. Applications

8. Conclusion

1. INTRODUCTION

First, technology related to D2D communication will be described withreference to FIGS. 1 to 7.

(Use Case of D2D Communication)

In general LTE systems, an evolved Node B (eNB) and a user equipment(UE) perform radio communication, but UEs do not perform radiocommunication to each other. However, a method in which the UEs directlyperform radio communication to each other is necessary for anapplication for public safety (for example, an application such ascollision avoidance) or data offloading.

Use cases of D2D communication are discussed in 3GPP service and systemsaspects (SA) 1 and the like, and are described in TR 22.803. Also, in TR22.803, use cases are disclosed, but specific implementation methods arenot disclosed. Hereinafter, specific examples of the use case will bedescribed with reference to FIGS. 1 and 2.

FIG. 1 is a first explanatory diagram illustrating a specific example ofa use case of D2D communication. Referring to FIG. 1, multiple UEs 10and an eNB 20 are illustrated. As a first use case, for example, an UE10A and an UE 10B positioned within a network coverage area (forexample, inside a cell 21 of the eNB 20) perform D2D communication. SuchD2D communication is referred to as in-coverage D2D communication. As asecond use case, for example, an UE 10C and an UE 10D positioned outsideof the network coverage area perform D2D communication. Such D2Dcommunication is referred to as out-of-coverage D2D communication. As athird use case, for example, an UE 10E positioned within the networkcoverage area and an UE 10F positioned outside of the network coveragearea perform D2D communication. Such D2D communication is referred to aspartial-coverage D2D communication. From the viewpoint of public safety,out-of-coverage D2D communication and partial-coverage D2D communicationare also important. Also, the network coverage area refers to a coveragearea of a cellular network. That is, a set of cells builds the networkcoverage area.

FIG. 2 is a second explanatory diagram illustrating a specific exampleof a use case of D2D communication. Referring to FIG. 2, an UE 10A andan UE 10B, and an eNB 20A and an eNB 20B are illustrated. In thisexample, the eNB 20A is operated by a first mobile network operator(MNO) and the eNB 20B is operated by a second MNO. Then, the UE 10Apositioned within a first network coverage area (for example, inside acell 21A of the eNB 20A) and the UE 10B positioned within a secondnetwork coverage area (for example, inside a cell 21B of the eNB 20B)perform D2D communication. From the viewpoint of public safety, such D2Dcommunication is also important.

(Flow Up to D2D Communication)

For example, synchronization, discovery, and connection establishmentare sequentially performed, and then D2D communication is performed.Hereinafter, considerations of steps of synchronization, discovery, andconnection establishment will be described.

(a) Synchronization

When two UEs are positioned within the network coverage area, the twoUEs obtain synchronization with the eNB using a downlink signal from theeNB and thus are able to be synchronized to each other to some extent.

On the other hand, when at least one of two UEs attempting to performD2D communication is positioned outside of the network coverage area, atleast one of the two UEs is necessary to transmit a synchronizationsignal for synchronization in D2D communication.

(b) Discovery of Other UEs

Discovery of other UEs is performed by, for example, transmitting andreceiving a discovery signal. More specifically, for example, one UE ofthe two UEs transmits the discovery signal, and the other UE of the twoUEs receives the discovery signal and attempts to communicate with theone UE.

The discovery signal is preferably transmitted at a predetermined timingin a time direction. Accordingly, it is possible to restrict a timing atwhich the UE of a reception side attempts to receive the discoverysignal. Also, as the assumption, two UEs attempting to perform D2Dcommunication may obtain synchronization in advance before the discoverysignal is received.

(c) Connection Establishment

The two UEs attempting to perform D2D communication may establish aconnection, for example, as follows. First, a first UE transmits adiscovery signal and a second UE receives the discovery signal. Then,the second UE transmits a request message requesting connectionestablishment to the first UE. Then, the first UE transmits a completionmessage indicating completion of connection establishment to the secondUE in response to the request message.

(Synchronization Signal Transmitted by eNB)

In LTE, the eNB transmits a primary synchronization signal (PSS) and asecondary synchronization signal (SSS) as a synchronization signal. ThePSS and the SSS are transmitted at a predetermined timing in a framestructure of a radio frame. Hereinafter, a specific example of timingsof the PSS and the SSS in frequency division duplex (FDD) and timedivision duplex (TDD) will be described with reference to FIGS. 3 and 4.

FIG. 3 is an explanatory diagram illustrating exemplary timings of a PSSand an SSS in FDD. Referring to FIG. 3, 10 subframes included in theradio frame are illustrated. In FDD, in subframes (that is, a firstsubframe and a sixth subframe) having subframe numbers 0 and 5, the PSSand the SSS are transmitted. More specifically, the SSS is transmittedin a sixth symbol of a first slot included in each of the subframes, andthe PSS is transmitted in a seventh symbol of the first slot.

FIG. 4 is an explanatory diagram illustrating exemplary timings of a PSSand an SSS in TDD. Referring to FIG. 4, 10 subframes included in theradio frame are illustrated. In TDD, in subframes (that is, a secondsubframe and a seventh subframe) of subframe numbers 1 and 6, the PSS istransmitted. More specifically, in a third symbol of a first slotincluded in each subframe, the PSS is transmitted. In addition, in TDD,in subframes (that is, a first subframe and a sixth subframe) ofsubframe numbers 0 and 5, the SSS is transmitted. More specifically, ina seventh symbol of a second slot included in each subframe, the SSS istransmitted.

When the PSS is detected, the UE can recognize a timing of eachsubframe. In addition, when the SSS is detected, the UE can recognizewhich subframe is a subframe #0.

Furthermore, the UE can identify a cell group to which a cell formed bythe eNB that transmits the PSS belongs among three cell groups based ona sequence of the PSS. In addition, the UE can identify a cell formed bythe eNB that transmits the SSS among 168 cell candidates that belong toone cell group based on a sequence of the SSS. That is, the UE canidentify a cell formed by the eNB that transmits the PSS and the SSSamong 504 cell candidates based on the sequence of the PSS and thesequence of the SSS.

(Synchronization Signal of D2D Communication)

For example, when the UE is positioned within the network coverage area,synchronization for D2D communication is performed based on thesynchronization signal transmitted by the eNB. For example, when the UEis positioned outside of the network coverage area, synchronization forD2D communication is performed based on the synchronization signaltransmitted by another UE. Also, the synchronization signal may be arelayed signal.

The synchronization signal used by a terminal device for D2Dcommunication may have various attributes. For example, thesynchronization signal may have an attribute of a transmission source.The transmission source may be the eNB or the UE. For example, thesynchronization signal may have an attribute of presence or absence ofrelay.

When the synchronization signal is wirelessly relayed, deterioration ofprecision of a center frequency is concerned. Accordingly, it ispreferable that the number of relays (the number of hops) be smaller.

The eNB is more preferable than the UE as the transmission source of thesynchronization signal. This is because precision of an oscillator ofthe eNB is higher than precision of an oscillator of the UE.

(Radio Resources Available for D2D Communication)

(a) Resource Pool

As radio resources available for D2D communication, radio resourcescalled a resource pool are prepared. As the resource pool, periodicradio resources are considered. For example, the resource pool isrepresented by a period and an offset (in a time direction).

As a method of using the resource pool, two methods may be provided. Inthe first method, a management node (for example, the eNB or the UE)allocates radio resources among the resource pool to the UE and notifiesthe UE of the radio resources. The UE can perform D2D communication inthe allocated radio resources. In the second method, the UE selectsradio resources from among the resource pool, and performs D2Dcommunication in the radio resources. The first method is anon-contention-based method and there is no collision. On the otherhand, the second method is a contention-based method, and collision mayoccur.

(b) Multiple Resource Pools

It is considered natural that multiple resource pools are prepared. Inthis case, the period and the offset of the resource pool may bedifferent from periods and offsets of other resource pools. Also, theperiod of the resource pool may be the same as periods of other resourcepools while the offset of the resource pool is different from offsets ofthe other resource pools.

Hereinafter, the radio frame and the subframe serving as a unit of timein a cellular system will be described with reference to FIG. 5. Aspecific example of the resource pool will be described with referenceto FIG. 6.

FIG. 5 is an explanatory diagram illustrating a radio frame andsubframes in a cellular system. Referring to FIG. 5, the radio frame and10 subframes included in one radio frame are illustrated. Each radioframe is 10 ms, and each subframe is 1 ms. Each radio frame has a systemframe number (SFN) of any of 0 to 1023, and 1024 radio frames arerepeatedly presented.

FIG. 6 is an explanatory diagram illustrating an exemplary resourcepool. Referring to FIG. 6, two resource pools (that is, a resource pool#1 and a resource pool #2) are illustrated. The radio resourcesavailable for D2D communication are considered to be periodicallyarranged in the subframe. For example, the resource pool #1 includesradio resources of subframes 31 that are repeated at a period 33, andthe resource pool #2 includes radio resources of subframes 35 that arerepeated at a period 37. For example, the period 33 is 200 ms, and theperiod 37 is 400 ms. Also, in this example, the resource pool #1 and theresource pool #2 have different offsets.

(c) Signal/Information Transmitted in Resource Pool

For example, in the resource pool, a synchronization signal andsynchronization information (information of synchronization) aretransmitted by a representative UE. In addition, the UE performs D2Dcommunication in radio resources other than the radio resources in whichthe synchronization signal and the synchronization information aretransmitted among the resource pool. Hereinafter, a specific examplethereof will be described with reference to FIG. 7.

FIG. 7 is an explanatory diagram illustrating an example of a signal andinformation transmitted in a resource pool. Referring to FIG. 7, Nresource pools (that is, resource pools #1 to #N) are illustrated. Ineach of the N resource pools, the synchronization signal and thesynchronization information are transmitted. In addition, in each of theN resource pools, D2D communication may be performed in radio resourcesother than the radio resources in which the synchronization signal andthe information are transmitted. Also, one UE may transmit thesynchronization signal and the synchronization information in two ormore resource pools.

2. TECHNICAL PROBLEMS ACCORDING TO EMBODIMENTS OF PRESENT DISCLOSURE

First, technical problems according to embodiments of the presentdisclosure will be described with reference to FIG. 8.

(Premises)

For example, as radio resources available for D2D communication,periodic radio resources are allocated. For example, at periods of aninteger multiple of a radio frame, radio resources of a specificsubframe are allocated as the radio resources available for D2Dcommunication. Therefore, D2D communication is performed in the specificsubframe.

For example, when D2D communication is performed in a TDD carrier, radioresources of an uplink subframe of a UL/DL configuration of the TDDcarrier are allocated as the radio resources available for D2Dcommunication within a network coverage area. Therefore, D2Dcommunication is performed in the uplink subframe. A specific examplethereof will be described below with reference to FIG. 8.

FIG. 8 is an explanatory diagram illustrating a UL/DL configuration.Referring to FIG. 8, seven configurations (configurations 0 to 6) thatmay be selected as the UL/DL configuration of the TDD carrier areillustrated. In each of the configurations, each of 10 subframesincluded in a radio frame is determined as a downlink subframe, anuplink subframe or a special subframe. As an example, when the UL/DLconfiguration of the TDD carrier is the configuration 2, radio resourcesof any of subframes having subframe numbers 2 and 7 are allocated as theradio resources available for D2D communication. As another example,when the UL/DL configuration of the TDD carrier is the configuration 3,radio resources of any of subframes having subframe numbers 2, 3, and 4are allocated as the radio resources available for D2D communication.

(First Technical Problem)

In the case of in-coverage, the base station may notify the terminaldevice of the radio resources available for D2D communication. However,when the base station freely selects the radio resources available forD2D communication without constraints, the base station may use manyradio resources in order to notify the radio resources available for D2Dcommunication. As a result, from the viewpoint of the radio resources, aload on the base station may become large.

Referring again to FIG. 8, for example, when the UL/DL configuration ofthe TDD carrier is the configuration 2, radio resources of a subframehaving a subframe number 7 are allocated as the radio resourcesavailable for D2D communication. Then, the UL/DL configuration ischanged from the configuration 2 to the configuration 3. Therefore, thesubframe having a subframe number 7 becomes the downlink subframe. As aresult, D2D communication may be performed in the downlink subframe.

Accordingly, it is preferable to provide a mechanism in which theterminal device can appropriately perform D2D communication under a TDDenvironment. More specifically, for example, it is preferable to providea mechanism in which the terminal device can continuously perform D2Dcommunication in the uplink subframe under the TDD environment.

(Second Technical Problem)

In addition, when radio resources of the uplink subframe of the UL/DLconfiguration of the TDD carrier are freely allocated as the radioresources available for D2D communication, a negative influence mayoccur in TDD radio communication between the base station and theterminal device.

For example, when the uplink subframe is allocated for D2Dcommunication, the terminal device transmits no uplink signal in theuplink subframe. Therefore, for example, communication quality in anuplink of the terminal device may decrease. As an example, when a userof the terminal device makes a call, a transmission interval of audiodata by the terminal device may be longer. Therefore, a delay may occurwhen audio data is transmitted. As a result, communication quality maydecrease. As another example, transmission of ACK/NACK (that is,ACK/NACK of downlink data) by the terminal device in an uplink at anappropriate timing is considered to be difficult. Specifically, errorsor delays are considered to occur when ACK/NACK is transmitted in theuplink

Accordingly, it is preferable to provide a mechanism in which theterminal device can appropriately perform D2D communication under theTDD environment. More specifically, for example, it is preferable toprovide a mechanism in which a negative influence occurring in TDD radiocommunication between the base station and the terminal device due toD2D communication can be reduced.

2. SCHEMATIC CONFIGURATION OF COMMUNICATION SYSTEM

Next, a schematic configuration of a communication system 1 according toan embodiment of the present disclosure will be described with referenceto FIG. 9. FIG. 9 is an explanatory diagram illustrating an example of aschematic configuration of the communication system 1 according to theembodiment of the present disclosure. Referring to FIG. 9, thecommunication system 1 includes a base station 100 and a terminal device200. The communication system 1 is, for example, a cellular system, andis a system compliant with, for example, LTE, LTE-Advanced, orcommunication standards conforming thereto.

(The Base Station 100)

The base station 100 performs radio communication with the terminaldevice. For example, the base station 100 performs radio communicationwith the terminal device 200 which is positioned inside a cell 101 ofthe base station 100.

Especially, in the embodiment of the present disclosure, the basestation 100 performs radio communication in TDD. Specifically, forexample, the base station 100 uses the TDD carrier, transmits a downlinksignal in the downlink subframe, and receives an uplink signal in theuplink subframe. The TDD carrier is a carrier for TDD radiocommunication, for example, a component carrier.

Also, in FIG. 9, only one base station (that is, the base station 100)included in the communication system 1 is illustrated. It is needless tosay that the communication system 1 may include multiple base stations.Then, a set of multiple base stations builds the network coverage area(that is, a coverage area of the cellular network).

(The Terminal Device 200)

The terminal device 200 performs radio communication with the basestation. For example, when the terminal device 200 is positioned insidethe cell 101 of the base station 100, the terminal device 200 performsradio communication with the base station 100. For example, the terminaldevice 200 performs radio communication with the base station in TDD.Specifically, for example, the terminal device 200 uses the TDD carrier,receives a downlink signal in the downlink subframe, and transmits anuplink signal in the uplink subframe.

Especially, in the embodiment of the present disclosure, the terminaldevice 200 performs D2D communication. For example, the terminal device200 performs D2D communication with another terminal device 200.

4. CONFIGURATION OF RESPECTIVE DEVICES

Next, exemplary configurations of the base station 100 and the terminaldevice 200 will be described with reference to FIGS. 10 to 11.

<4.1. Base Station Configuration>>

FIG. 10 is a block diagram illustrating an exemplary configuration ofthe base station 100 according to the embodiment of the presentdisclosure. Referring to FIG. 10, the base station 100 includes anantenna unit 110, a radio communication unit 120, a networkcommunication unit 130, a storage unit 140 and a processing unit 150.

(The Antenna Unit 110)

The antenna unit 110 receives a radio signal and outputs the receivedradio signal to the radio communication unit 120. In addition, theantenna unit 110 transmits a transmission signal output by the radiocommunication unit 120.

(The Radio Communication Unit 120)

The radio communication unit 120 transmits and receives a signal. Forexample, the radio communication unit 120 transmits a downlink signal tothe terminal device and receives an uplink signal from the terminaldevice.

(The Network Communication Unit 130)

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toother nodes and receives information from other nodes. For example, theother nodes include other base stations and a core network node.

(The Storage Unit 140)

The storage unit 140 stores a program and data for operating the basestation 100.

(The Processing Unit 150)

The processing unit 150 provides various functions of the base station100. The processing unit 150 includes an information acquisition unit151 and a control unit 153. Also, the processing unit 150 may furtherinclude a component other than these components. That is, the processingunit 150 may also perform an operation other than operations of thesecomponents.

Operations of the information acquisition unit 151 and the control unit153 will be described later in detail.

<4.2. Terminal Device Configuration>>

FIG. 11 is a block diagram illustrating an exemplary configuration ofthe terminal device 200 according to the embodiment of the presentdisclosure. Referring to FIG. 11, the terminal device 200 includes anantenna unit 210, a radio communication unit 220, a storage unit 230 anda processing unit 240.

(The Antenna Unit 210)

The antenna unit 210 receives a radio signal and outputs the receivedradio signal to the radio communication unit 220. In addition, theantenna unit 210 transmits a transmission signal output by the radiocommunication unit 220.

(The Radio Communication Unit 220)

The radio communication unit 220 transmits and receives a signal. Forexample, the radio communication unit 220 receives a downlink signalfrom the base station and transmits an uplink signal to the basestation. In addition, for example, the radio communication unit 220receives a signal from another terminal device and transmits a signal toanother terminal device.

(The Storage Unit 230)

The storage unit 230 stores a program and data for operating theterminal device 200.

(The Processing Unit 240)

The processing unit 240 provides various functions of the terminaldevice 200. The processing unit 240 includes an information acquisitionunit 241 and a control unit 243. Also, the processing unit 240 mayfurther include a component other than these components. That is, theprocessing unit 240 may also perform an operation other than operationsof these components.

Operations of the information acquisition unit 241 and the control unit243 will be described later in detail.

5. TECHNICAL FEATURES ACCORDING TO EMBODIMENTS OF PRESENT DISCLOSURE

Next, technical features according to embodiments of the presentdisclosure will be described with reference to FIGS. 12 to 19.

<5.1. First Technical Features>

First, the first technical features according to the embodiment of thepresent disclosure will be described with reference to FIGS. 12 to 15.The first technical features are, for example, features that correspondto the first technical problem according to the embodiment of thepresent disclosure described above.

(Dynamic Change of UL/DL Configuration)

The base station 100 (the control unit 153) dynamically changes theUL/DL configuration of the TDD carrier.

(a) Multiple Configurations

For example, the base station 100 (the control unit 153) changes theUL/DL configuration from one configuration among multiple configurationsto another configuration among the multiple configurations.

For example, the multiple configurations include seven configurations(configurations 0 to 6) illustrated in FIG. 8. That is, the base station100 (the control unit 153) changes the UL/DL configuration from oneconfiguration among the seven configurations to another configuration.

As a specific process, for example, the control unit 153 changes theUL/DL configuration by changing an operation parameter designating theUL/DL configuration. Also, this is only an example of a specificprocess, and it is needless to say that the control unit 153 may performanother process according to mounting.

(b) Notification of UL/DL Configuration

For example, the base station 100 (the control unit 153) notifies theterminal device of the UL/DL configuration of the TDD carrier.

(b-1) Notification Method

Reporting System Information

For example, the base station 100 (the control unit 153) notifies theterminal device of the UL/DL configuration by reporting systeminformation indicating the UL/DL configuration. For example, the systeminformation is a system information block (SIB) 1.

Accordingly, for example, not only the terminal device in a connectionmode but also the terminal device in an idle mode can recognize theUL/DL configuration.

Separate Signaling

The base station 100 (the control unit 153) may notify the terminaldevice in a connection mode of the UL/DL configuration using separatesignaling in addition to reporting the system information. The separatesignaling may be radio resource control (RRC) signaling. The terminaldevice in a connection mode may be, for example, the terminal device200.

Accordingly, for example, it is possible to notify of a change in theUL/DL configuration quickly.

(b-2) Operation of the Terminal Device 200

For example, the terminal device 200 (the information acquisition unit241) acquires the UL/DL configuration. Therefore, the terminal device200 (the control unit 243) performs radio communication with the basestation using the TDD carrier according to the UL/DL configuration.

(Notification of Radio Resources for D2D Communication)

The base station 100 (the control unit 153) notifies the terminal deviceof the radio resources for D2D communication appropriate for the UL/DLconfiguration. The radio resources are radio resources of the TDDcarrier. Also, “radio resources for D2D communication” may be simplyreferred to as “D2D resources” below.

On the other hand, the terminal device 200 (the information acquisitionunit 241) acquires information indicating the D2D resources appropriatefor the UL/DL configuration (that is, the UL/DL configuration of the TDDcarrier that is dynamically changed by the base station 100). Therefore,the terminal device 200 performs D2D communication using the D2Dresources. The control unit 243 of the terminal device 200 controls D2Dcommunication using the D2D resources.

(a) D2D Resources Appropriate for UL/DL Configuration

The D2D resources appropriate for the UL/DL configuration are radioresources of at least one uplink subframe of the UL/DL configuration.

Referring again to FIG. 8, as an example, when the UL/DL configurationis the configuration 1, the D2D resources appropriate for the UL/DLconfiguration are radio resources of at least one subframe amongsubframes having subframe numbers 2, 3, 7, and 8. As another example,when the UL/DL configuration is the configuration 4, the D2D resourcesappropriate for the UL/DL configuration are radio resources of at leastone subframe among subframes having subframe numbers 2 and 3.

Also, for example, the D2D resources are periodic radio resources. Morespecifically, for example, the D2D resources are radio resources thatare repeated at periods of an integer multiple of a radio frame. In thiscase, as long as the period is not one radio frame, the D2D resourcesare radio resources of a specific subframe of a limited radio frame. TheD2D resources may be referred to as a resource pool. Multiple resourcepools each having a period (and an offset) may be prepared. The D2Dresources may be indicated by a period (and an offset) of a radio frameand a subframe.

(b) Notification Method

For example, the base station 100 (the control unit 153) notifies theterminal device of the D2D resources by reporting system informationindicating the D2D resources appropriate for the UL/DL configuration.Accordingly, for example, not only the terminal device in a connectionmode but also the terminal device in an idle mode can recognize the D2Dresources.

Also, the base station 100 (the control unit 153) may notify theterminal device 200 of the D2D resources using separate signaling. Theseparate signaling may be RRC signaling.

(c) Notification Form

(c-1) Notification of D2D Resources According to Change of the UL/DLConfiguration

As described above, the base station 100 (the control unit 153) changesthe UL/DL configuration from one configuration among the multipleconfigurations to another configuration among the multipleconfigurations.

As a first notification form, for example, the base station 100 (thecontrol unit 153) notifies the terminal device of the D2D resourcesappropriate for the other configuration according to a change of theUL/DL configuration. The D2D resources appropriate for the otherconfiguration are radio resources of at least one uplink subframe of theother configuration.

On the other hand, the terminal device 200 (the information acquisitionunit 241) acquires information indicating the D2D resources of which thebase station 100 has notified the terminal device 200. Therefore, theterminal device 200 uses the D2D resources of which the base station 100has notified the terminal device 200, and performs D2D communication.That is, the control unit 243 of the terminal device 200 controls D2Dcommunication using the D2D resources of which the base station 100 hasnotified the terminal device 200.

A specific example of the D2D resources of which the base station 100has notified the terminal device will be described below with referenceto FIGS. 12 and 13.

FIG. 12 is an explanatory diagram illustrating a first example of D2Dresources. Referring to FIG. 12, configurations 0 to 6 are illustrated.In this example, one uplink subframe is prepared as the D2D resourcesfor each configuration. For example, the D2D resources appropriate foreach of the configurations 0, 1, 3, 4 and 6 are radio resources of anuplink subframe having a subframe number 3. In addition, for example,the D2D resources appropriate for each of the configurations 2 and 5 areradio resources of an uplink subframe having a subframe number 2.

FIG. 13 is an explanatory diagram illustrating a notification example ofthe D2D resources according to the change of the UL/DL configuration.Referring to FIG. 13, for example, the UL/DL configuration of the TDDcarrier is changed from the configuration 0 to the configuration 2. TheD2D resources appropriate for the configuration 0 are radio resources ofa subframe having a subframe number 3. The D2D resources appropriate forthe configuration 2 are radio resources of a subframe having a subframenumber 2. In this case, the base station 100 (the control unit 153)notifies the terminal device of radio resources of an uplink subframehaving a subframe number 2 as the D2D resources according to the changeof the UL/DL configuration. As a result, the terminal device 200 doesnot perform D2D communication in a subframe having a subframe number 3after the change of the UL/DL configuration, but performs D2Dcommunication in a subframe having a subframe number 2.

In this manner, for example, when the UL/DL configuration is changed toany of the configurations 0, 1, 3, 4 and 6, the base station 100 (thecontrol unit 153) notifies the terminal device of radio resources of anuplink subframe having a subframe number 3 as the D2D resources. Inaddition, for example, when the UL/DL configuration is changed to any ofthe configurations 2 and 5, the base station 100 (the control unit 153)notifies the terminal device of radio resources of an uplink subframehaving a subframe number 2 as the D2D resources.

Also, in the example of FIG. 12, the D2D resources are radio resourcesof one subframe within a radio frame. However, it is needless to saythat the D2D resources may be radio resources of two or more subframeswithin a radio frame.

In addition, for example, the D2D resources are periodic radio resourcesand have a period (and an offset). In this case, for example, the basestation 100 (the control unit 153) notifies of not only the subframe butalso the period (and the offset) when the D2D resources are notified of.For example, the period is a period of an integer multiple of a radioframe.

As described above, for example, the base station 100 (the control unit153) notifies the terminal device of the D2D resources appropriate forthe other configuration (that is, the changed configuration) accordingto the change of the UL/DL configuration. Accordingly, for example, theterminal device can continuously perform D2D communication in the uplinksubframe under the TDD environment. That is, even when a UL/DL subframeof the TDD carrier is changed, the base station 100 notifies theterminal device 200 of the D2D resources (the radio resources of theuplink subframe) appropriate for the changed configuration, and theterminal device 200 can perform D2D communication in the uplinksubframe.

Also, for example, the base station 100 reports system informationindicating the other configuration (that is, the changed configuration)from immediately before the change of the UL/DL configuration toimmediately before the following change of the UL/DL configuration. Thebase station 100 may notify the terminal device 200 of the otherconfiguration (that is, the changed configuration) using separatesignaling immediately before the change of the UL/DL configuration.

(c-2) Notification of D2D Resources Appropriate for Each of the MultipleConfigurations

As described above, the base station 100 (the control unit 153) changesthe UL/DL configuration from one configuration among the multipleconfigurations to another configuration among the multipleconfigurations.

As a second notification form, for example, the base station 100 (thecontrol unit 153) notifies the terminal device of the D2D resourcesappropriate for each of the multiple configurations.

First Example: D2D Resources for Each Configuration

As a first example, the radio resources appropriate for each of themultiple configurations include the D2D resources for eachconfiguration. That is, the base station 100 (the control unit 153)notifies the terminal device of the D2D resources for each configurationincluded in the multiple configurations.

Referring again to FIG. 12, for example, the multiple configurations arethe configurations 0 to 6. The D2D resources for each configuration areillustrated. For example, the base station 100 (the control unit 153)notifies the terminal device of the D2D resources for each of theseconfigurations.

On the other hand, the terminal device 200 (the information acquisitionunit 241) acquires information indicating the D2D resources appropriatefor the UL/DL configuration among the D2D resources appropriate for eachof the multiple configurations based on the UL/DL configuration of whichthe base station 100 has notified the terminal device. Therefore, theterminal device 200 performs D2D communication using the D2D resources.

Referring again to FIG. 13, for example, the UL/DL configuration of theTDD carrier is changed from the configuration 0 to the configuration 2.In this case, the base station 100 notifies the terminal device of theconfiguration 2, and the terminal device 200 (the informationacquisition unit 241) acquires information indicating the D2D resourcesappropriate for the configuration 2 among the D2D resources appropriatefor each of the configurations 0 to 6. Therefore, the terminal device200 performs D2D communication in the D2D resources appropriate for theconfiguration 2.

In addition, for example, the D2D resources are periodic radio resourcesand have a period (and an offset). In this case, for example, the basestation 100 (the control unit 153) notifies of not only the subframe butalso the period (and the offset) when the D2D resources are notified of.For example, the period is a period of an integer multiple of a radioframe.

As described above, the base station 100 (the control unit 153) notifiesthe terminal device of the D2D resources for each configuration includedin the multiple configurations. Accordingly, for example, the terminaldevice can continuously perform D2D communication in the uplink subframeunder the TDD environment. That is, even when the UL/DL subframe of theTDD carrier is changed, the terminal device 200 can specify the D2Dresources (the radio resources of the uplink subframe) appropriate forthe changed configuration, and perform D2D communication in the uplinksubframe.

Second Example: D2D Resources Common Among Multiple Configurations

As a second example, the radio resources appropriate for each of themultiple configurations may be radio resources of at least one uplinksubframe common among the multiple configurations. That is, the basestation 100 (the control unit 153) may notify the terminal device ofradio resources of at least one uplink subframe common among themultiple configurations as the D2D resources.

On the other hand, the terminal device 200 (the information acquisitionunit 241) may acquire information indicating the D2D resources (that is,radio resources of at least one uplink subframe common among themultiple configurations) of which the base station 100 has notified theterminal device. Therefore, the terminal device 200 may use the D2Dresources of which the base station 100 has notified the terminal device200 and perform D2D communication. That is, the control unit 243 of theterminal device 200 may control D2D communication using the D2Dresources of which the base station 100 has notified the terminal device200.

A specific example of the D2D resources will be described below withreference to FIG. 14.

FIG. 14 is an explanatory diagram illustrating a second example of theD2D resources. Referring to FIG. 14, configurations 0 to 6 areillustrated. In this example, radio resources of an uplink subframe(that is, a subframe having a subframe number 2) common among theconfigurations 0 to 6 are prepared as the D2D resources. In this case,the base station 100 notifies the terminal device of radio resources ofan uplink subframe having a subframe number 2 as the D2D resources.Accordingly, either before the change or after the change of the UL/DLsubframe of the TDD carrier, the terminal device 200 can perform D2Dcommunication in the uplink subframe having the subframe number 2.

While the example in which a subframe common among the multipleconfigurations is a subframe having a subframe number 2 has beendescribed, the subframe common among the multiple configurations is notlimited thereto. For example, the multiple configurations may not beseven configurations (that is, the configurations 0 to 6), but may besome of the seven configurations. Therefore, the subframe common amongthe multiple configurations may be a subframe other than the subframehaving a subframe number 2. A specific example thereof will be describedbelow with reference to FIG. 15.

FIG. 15 is an explanatory diagram illustrating a third example of theD2D resources. Referring to FIG. 15, the configurations 0, 1, 3, 4 and 6are illustrated. In this example, the multiple configurations are theconfigurations 0, 1, 3, 4 and 6. Therefore, radio resources of an uplinksubframe (for example, a subframe having a subframe number 3) commonamong the configurations 0, 1, 3, 4 and 6 are prepared as the D2Dresources. In this case, the base station 100 notifies the terminaldevice of radio resources of an uplink subframe having a subframe number3 as the D2D resources. Accordingly, either before the change or afterthe change of the UL/DL subframe of the TDD carrier, the terminal device200 can perform D2D communication in the uplink subframe having thesubframe number 3.

In addition, for example, the D2D resources are periodic radio resourcesand have a period (and an offset). In this case, for example, the basestation 100 (the control unit 153) notifies of not only the subframe butalso the period (and the offset) when the D2D resources are notified of.For example, the period is a period of an integer multiple of a radioframe.

As described above, the base station 100 (the control unit 153) maynotify the terminal device of radio resources of at least one uplinksubframe common among the multiple configurations as the D2D resources.Accordingly, for example, the terminal device can continuously performD2D communication in the uplink subframe under the TDD environment. Thatis, either before the change or after the change of the UL/DL subframeof the TDD carrier, the terminal device 200 can perform D2Dcommunication in the uplink subframe.

Also, for example, a period (and an offset) of the D2D resources may becommon among the multiple configurations. That is, the D2D resourcescommon among the multiple configurations may also be prepared.Accordingly, for example, regardless of the change of UL/DLconfiguration, the terminal device can perform D2D communication in theD2D resources.

As described above, the base station 100 (the control unit 153) notifiesthe terminal device of the D2D resources appropriate for the UL/DLconfiguration. Also, for example, the D2D resources refer to a resourcepool having a period (and an offset), and the base station 100 (thecontrol unit 153) may notify the terminal device of the resource pool(the D2D resources) appropriate for the UL/DL configuration in each ofmultiple resource pools.

<5.1. Second Technical Features>

Next, the second technical features according to the embodiment of thepresent disclosure will be described with reference to FIGS. 16 to 19.The second technical features are, for example, features that correspondto the second technical problem according to the embodiment of thepresent disclosure described above.

(D2D Resources Appropriate for UL/DL Configuration)

As described above, the base station 100 (the control unit 153) notifiesthe terminal device of the radio resources for D2D communicationappropriate for the UL/DL configuration (the D2D resources). Inaddition, the D2D resources appropriate for the UL/DL configuration arethe radio resources of at least one uplink subframe of the UL/DLconfiguration.

(a) Features of Subframe

(a-1) Some of Two or More Successive Uplink Subframes

For example, each of the at least one uplink subframe is included in twoor more successive uplink subframes of the UL/DL configuration. That is,the D2D resources appropriate for the UL/DL configuration are radioresources of at least one uplink subframe included in each of the two ormore successive uplink subframes of the UL/DL configuration. Also, oneor more uplink subframes among the two or more successive uplinksubframes are not included in the at least one uplink subframe. Aspecific example of the D2D resources will be described below withreference to FIG. 16.

FIG. 16 is an explanatory diagram illustrating a fourth example of theD2D resources. Referring to FIG. 16, configurations 0 to 6 areillustrated. For example, the D2D resources appropriate for theconfiguration 0 are radio resources of subframes having subframe numbers3 and 8. In the configuration 0, a subframe having a subframe number 3is included in three successive uplink subframes, and a subframe havinga subframe number 8 is also included in three successive uplinksubframes. The D2D resources appropriate for the configuration 1 areradio resources of subframes having subframe numbers 3 and 8. The D2Dresources appropriate for the configurations 3 and 4 are radio resourcesof a subframe having a subframe number 3. The D2D resources appropriatefor the configuration 6 are radio resources of subframes having subframenumbers 3 and 7.

Accordingly, for example, it is possible to decrease a negativeinfluence occurring in TDD radio communication between the base stationand the terminal device due to D2D communication. More specifically, forexample, even when the uplink subframe is unable to be used in TDD radiocommunication due to D2D communication, a maximum interval between theuplink subframes used in TDD radio communication hardly becomes longer.Therefore, a decrease in uplink communication quality due to an increasein the interval of the uplink subframe is suppressed.

Limitation of D2D Communication

For example, when the UL/DL configuration includes two or moresuccessive uplink subframes, the base station 100 (the control unit 153)notifies the terminal device of the D2D resources appropriate for theUL/DL configuration. On the other hand, when the UL/DL configurationdoes not include two or more successive uplink subframes, the basestation 100 (the control unit 153) does not notify the terminal deviceof the D2D resources appropriate for the UL/DL configuration.

That is, when the UL/DL configuration includes two or more successiveuplink subframes, D2D communication is performed, and when the UL/DLconfiguration does not include two or more successive uplink subframes,no D2D communication is performed.

Referring again to FIG. 16, for example, when the UL/DL configuration ofthe TDD carrier is any of the configurations 0, 1, 3, 4 and 6, the basestation 100 (the control unit 153) notifies the terminal device of theD2D resources appropriate for the UL/DL configuration. On the otherhand, when the UL/DL configuration of the TDD carrier is any of theconfigurations 2 and 5, the base station 100 (the control unit 153) doesnot notify the terminal device of the D2D resources appropriate for theUL/DL configuration. That is, when the UL/DL configuration is any of theconfigurations 0, 1, 3, 4 and 6, D2D communication is performed, andwhen the UL/DL configuration is any of the configurations 2 and 5, noD2D communication is performed.

Accordingly, for example, radio resources of at least one uplinksubframe included in each of the two or more successive uplink subframesmay be used as the D2D resources.

Limitation of Configuration

Alternatively, the UL/DL configuration of the TDD carrier may be aconfiguration including two or more successive uplink subframes.

Referring again to FIG. 16, for example, the UL/DL configuration of theTDD carrier may be any of the configurations 0, 1, 3, 4 and 6. That is,the configurations 2 and 5 that do not include two or more successiveuplink subframes may be excluded.

Accordingly, for example, radio resources of at least one uplinksubframe included in each of the two or more successive uplink subframesmay be used as the D2D resources.

(a-2) Number of Uplink Subframes

As described above, the D2D resources appropriate for the UL/DLconfiguration are radio resources of at least one uplink subframe of theUL/DL configuration.

The number of uplink subframes included in the at least one uplinksubframe may be different according to the number of uplink subframes ofthe UL/DL configuration.

For example, when the number of uplink subframes of the UL/DLconfiguration is greater, the D2D resources appropriate for the UL/DLconfiguration may be radio resources of a greater number of uplinksubframes. A specific example of the D2D resources will be describedbelow with reference to FIG. 17.

FIG. 17 is an explanatory diagram illustrating a fifth example of theD2D resources. Referring to FIG. 17, configurations 0 to 6 areillustrated. For example, the configuration 0 includes six uplinksubframes. The configuration 1 includes four uplink subframes. Theconfiguration 2 includes two uplink subframes. The configuration 3includes three uplink subframes. The configuration 4 includes two uplinksubframes. The configuration 5 includes one uplink subframe. Theconfiguration 6 includes five uplink subframes. Since the configurations0, 1, and 6 include great numbers of uplink subframes (for example, fouror more uplink subframes), the D2D resources appropriate for each of theconfigurations 0, 1, and 6 are radio resources of two uplink subframes.On the other hand, since the configurations 2, 3, 4, and 5 include smallnumbers of uplink subframes (for example, three or fewer uplinksubframes), the D2D resources appropriate for each of the configurations2, 3, 4, and 5 are radio resources of one uplink subframe.

Accordingly, for example, it is possible to decrease a negativeinfluence occurring in TDD radio communication between the base stationand the terminal device due to D2D communication. More specifically, forexample, even when the uplink subframe is unable to be used in TDD radiocommunication due to D2D communication, the uplink subframe used in TDDradio communication may be ensured to some extent in any configuration.Therefore, according to the configuration, a situation in which theuplink subframe is absent or the number of uplink subframessignificantly decreases may be avoided. Therefore, a decrease in uplinkcommunication quality due to a decrease of the number of uplinksubframes may be suppressed.

Limitation of D2D Communication

When the number of uplink subframes of the UL/DL configuration is equalto or greater than a predetermined number, the base station 100 (thecontrol unit 153) may notify the terminal device of the D2D resourcesappropriate for the UL/DL configuration. On the other hand, when thenumber of uplink subframes of the UL/DL configuration is less than thepredetermined number, the base station 100 (the control unit 153) maynot notify the terminal device of the D2D resources appropriate for theUL/DL configuration.

That is, when the number of uplink subframes of the UL/DL configurationis equal to or greater than the predetermined number, D2D communicationmay be performed, and when the number of uplink subframes is less thanthe predetermined number, no D2D communication may be performed.

As an example, the predetermined number may be 3. In this case, when theUL/DL configuration is any of the configurations 0, 1, 3, and 6, thebase station 100 (the control unit 153) may notify the terminal deviceof the D2D resources appropriate for the UL/DL configuration. On theother hand, when the UL/DL configuration is any of the configurations 2,4, and 5, the base station 100 (the control unit 153) may not notify theterminal device of the D2D resources appropriate for the UL/DLconfiguration. That is, when the UL/DL configuration is any of theconfigurations 0, 1, 3, and 6, D2D communication may be performed, andwhen the UL/DL configuration is any of the configurations 2, 4, and 5,no D2D communication may be performed.

As another example, the predetermined number may be 2. In this case,when the UL/DL configuration is any of the configurations 0, 1, 2, 3, 4,and 6, the base station 100 (the control unit 153) may notify theterminal device of the D2D resources appropriate for the UL/DLconfiguration. On the other hand, when the UL/DL configuration is theconfiguration 5, the base station 100 (the control unit 153) may notnotify the terminal device of the D2D resources appropriate for theUL/DL configuration. That is, when the UL/DL configuration is any of theconfigurations 0, 1, 2, 3, 4, and 6, D2D communication may be performed,and when the UL/DL configuration is the configuration 5, no D2Dcommunication may be performed.

Accordingly, for example, although the number of uplink subframes of theconfiguration is small, it is possible to prevent the uplink subframefrom not being used in TDD radio communication due to D2D communication.

Limitation of Configuration

Alternatively, the UL/DL configuration may also be a configurationincluding a predetermined number or more of uplink subframes.

As an example, the predetermined number may be 3. In this case, theUL/DL configuration of the TDD carrier may be any of the configurations0, 1, 3, and 6. That is, the configurations 2, 4, and 5 in which thenumber of uplink subframes is less than 3 may be excluded.

As another example, the predetermined number may be 2. In this case, theUL/DL configuration of the TDD carrier may be any of the configurations0, 1, 2, 3, 4, and 6. That is, the configuration 5 in which the numberof uplink subframes is less than 2 may be excluded.

Accordingly, for example, although the number of uplink subframes of theconfiguration is small, it is possible to prevent the uplink subframefrom not being used in TDD radio communication due to D2D communication.

(b) Features of Period

The D2D resources appropriate for the UL/DL configuration may beperiodic radio resources that are repeated at periods corresponding tothe number of uplink subframes of the UL/DL configuration.

(b-1) First example

When the number of uplink subframes of the UL/DL configuration isgreater, a period of the D2D resources appropriate for the UL/DLconfiguration may be shorter. A specific example of the period for eachconfiguration will be described below with reference to FIG. 18.

FIG. 18 is an explanatory diagram illustrating a first example of theperiod for each configuration. Referring to FIG. 18, periods andsubframes of seven configurations (configurations 0 to 6) areillustrated. In this example, similar to the example illustrated in FIG.12, the D2D resources appropriate for each of the configurations areradio resources of one uplink subframe. For example, the configurations0, 1, and 6 include four or more uplink subframes, and a period of theD2D resources appropriate for the configurations 0, 1, and 6 is 100 ms(that is, 10 radio frames). The configurations 2, 3, and 4 include twoor three uplink subframes, and a period of the D2D resources appropriatefor the configurations 0, 1, and 6 is 200 ms (that is, 20 radio frames).The configuration 5 includes one uplink subframe, and a period of theD2D resources appropriate for the configuration 5 is 400 ms (that is, 40radio frames).

Accordingly, for example, as the number of uplink subframes of theconfiguration is great, a greater number of D2D resources (the D2Dresources having a shorter period) are ensured. Therefore, an influenceof TDD radio communication between the base station and the terminaldevice may be suppressed and as many D2D resources as possible may beensured.

(b-2) Second Example

When the UL/DL configuration is a first configuration, the D2D resourcesappropriate for the UL/DL configuration may be radio resources of anuplink subframe of a first number and may be periodic radio resourcesthat are repeated at a first period. On the other hand, when the UL/DLconfiguration is a second configuration, the D2D resources appropriatefor the UL/DL configuration may be radio resources of an uplink subframeof a second number that is less than the first number and may beperiodic radio resources that are repeated at a second period that isshorter than the first period.

That is, the D2D resources have a longer period when the radio resourceshave a greater number of uplink subframes, and have a shorter periodwhen the radio resources have a smaller number of uplink subframes. Aspecific example of the period for each configuration will be describedbelow with reference to FIG. 19.

FIG. 19 is an explanatory diagram illustrating a second example of theperiod for each configuration. Referring to FIG. 19, periods andsubframes of seven configurations (configurations 0 to 6) areillustrated. For example, the configurations 0, 1, and 6 include four ormore uplink subframes, and the D2D resources appropriate for each of theconfigurations 0, 1, and 6 are radio resources of two uplink subframesand have a period of 400 ms (that is, 40 radio frames). In addition, theconfigurations 2, 3, 4, and 5 include three or fewer uplink subframes,and the D2D resources appropriate for each of the configurations 2, 3,4, and 5 are radio resources of one uplink subframe and have a period of200 ms (that is, 20 radio frames).

Accordingly, for example, when the number of uplink subframes of theconfiguration is small, the D2D resources are radio resources in which asmall number of uplink subframes are included in the radio frame andthat have a shorter period. Therefore, in an individual radio frame, aninfluence of TDD radio communication between the base station and theterminal device may be suppressed and a difference of amounts of the D2Dresources between configurations may decrease.

6. PROCESS FLOW

Next, process examples of embodiments of the present disclosure will bedescribed with reference to FIGS. 20 to 22.

First Example

FIG. 20 is a sequence diagram schematically illustrating a first exampleof a process flow according to the embodiment of the present disclosure.

The base station 100 reports system information indicating the firstconfiguration as the UL/DL configuration of the TDD carrier (S401). Inaddition, the base station 100 reports system information indicating theD2D resources appropriate for the first configuration (S403).

The terminal device 200 uses the D2D resources (that is, the D2Dresources appropriate for the first configuration) of which the basestation 100 has notified the terminal device 200, and performs D2Dcommunication (S405).

Then, the base station 100 determines changing of the UL/DLconfiguration of the TDD carrier from the first configuration to thesecond configuration, and reports system information indicating thesecond configuration as the UL/DL configuration (S407). In addition, thebase station 100 reports system information indicating the D2D resourcesappropriate for the second configuration (S409).

The terminal device 200 uses the D2D resources (that is, the D2Dresources appropriate for the second configuration) of which the basestation 100 has notified the terminal device 200, and performs D2Dcommunication (S411).

Second Example

FIG. 21 is a sequence diagram schematically illustrating a secondexample of a process flow according to the embodiment of the presentdisclosure.

The base station 100 reports system information indicating the firstconfiguration as the UL/DL configuration of the TDD carrier (S421). Inaddition, the base station 100 reports system information indicating theD2D resources appropriate for each of the multiple configurations(S423). Especially, in this example, the base station 100 reports systeminformation indicating the D2D resources for each configuration includedin the multiple configurations.

The terminal device 200 uses the D2D resources appropriate for the firstconfiguration among the D2D resources appropriate for each of themultiple configurations and performs D2D communication (S425).

Then, the base station 100 determines changing of the UL/DLconfiguration of the TDD carrier from the first configuration to thesecond configuration, and reports system information indicating thesecond configuration as the UL/DL configuration (S427).

The terminal device 200 uses the D2D resources appropriate for thesecond configuration among the D2D resources appropriate for each of themultiple configurations and performs D2D communication (S429).

Third Example

FIG. 22 is a sequence diagram schematically illustrating a third exampleof a process flow according to the embodiment of the present disclosure.

The base station 100 reports system information indicating the firstconfiguration as the UL/DL configuration of the TDD carrier (S441). Inaddition, the base station 100 reports system information indicating theD2D resources appropriate for each of the multiple configurations(S443). Especially, in this example, the base station 100 reports systeminformation indicating the radio resources of the uplink subframe commonamong the multiple configurations. Further, for example, the radioresources may be the D2D resources (that is, the D2D resources whosesubframe, period and offset are common among the multipleconfigurations) common among the multiple configurations.

The terminal device 200 uses the D2D resources (that is, the D2Dresources common among the multiple configurations) of which the basestation 100 has notified the terminal device 200 and performs D2Dcommunication (S445).

Also, for example, the base station 100 then changes the UL/DLconfiguration of the TDD carrier from the first configuration to thesecond configuration. Regardless of this change, the terminal device 200continuously uses the D2D resources (that is, the D2D resources commonamong the multiple configurations) and performs D2D communication.

7. APPLICATIONS

Technology according to one or more of the embodiments of the presentdisclosure is applicable to various products. A base station 100 may berealized as any type of evolved Node B (eNB) such as a macro eNB, and asmall eNB. A small eNB may be an eNB that covers a cell smaller than amacro cell, such as a pico eNB, micro eNB, or home (femto) eNB. Instead,the base station 100 may be realized as any other types of base stationssuch as a NodeB and a base transceiver station (BTS). The base station100 may include a main body (that is also referred to as a base stationdevice) configured to control radio communication, and one or moreremote radio heads (RRH) disposed in a different place from the mainbody. Additionally, various types of terminals to be discussed later mayalso operate as the base station 100 by temporarily or semi-permanentlyexecuting a base station function. Further, at least some of structuralelements of the base station 100 may be realized in the base stationdevice or in a module for the base station device.

For example, the terminal device 200 may be realized as a mobileterminal such as a smartphone, a tablet personal computer (PC), anotebook PC, a portable game terminal, a portable/dongle type mobilerouter, and a digital camera, or an in-vehicle terminal such as a carnavigation device. The terminal device 200 may also be realized as aterminal (that is also referred to as a machine type communication (MTC)terminal) that performs machine-to-machine (M2M) communication.Furthermore, at least some of structural elements of the terminal device200 may be a module (such as an integrated circuit module including asingle die) mounted on each of the terminals.

<7.1. Application Related to Base Station>

(First Application)

FIG. 23 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which an embodiment of the technology of thepresent disclosure may be applied. An eNB 800 includes one or moreantennas 810 and a base station device 820. Each antenna 810 and thebase station device 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the base station device 820 to transmit and receive radiosignals. The eNB 800 may include the multiple antennas 810, asillustrated in FIG. 23. For example, the multiple antennas 810 may becompatible with multiple frequency bands used by the eNB 800. AlthoughFIG. 23 illustrates the example in which the eNB 800 includes themultiple antennas 810, the eNB 800 may also include a single antenna810.

The base station device 820 includes a controller 821, a memory 822, anetwork interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of a higher layer of the base station device 820. Forexample, the controller 821 generates a data packet from data in signalsprocessed by the radio communication interface 825, and transfers thegenerated packet via the network interface 823. The controller 821 maybundle data from multiple base band processors to generate the bundledpacket, and transfer the generated bundled packet. The controller 821may have logical functions of performing control such as radio resourcecontrol, radio bearer control, mobility management, admission control,and scheduling. The control may be performed in corporation with an eNBor a core network node in the vicinity. The memory 822 includes RAM andROM, and stores a program that is executed by the controller 821, andvarious types of control data (such as a terminal list, transmissionpower data, and scheduling data).

The network interface 823 is a communication interface for connectingthe base station device 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800, and the core network node orthe other eNB may be connected to each other through a logical interface(such as an S1 interface and an X2 interface). The network interface 823may also be a wired communication interface or a radio communicationinterface for radio backhaul. If the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) and LTE-Advanced,and provides radio connection to a terminal positioned in a cell of theeNB 800 via the antenna 810. The radio communication interface 825 maytypically include, for example, a baseband (BB) processor 826 and an RFcircuit 827. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers (such as L1, medium access control (MAC), radiolink control (RLC), and a packet data convergence protocol (PDCP)). TheBB processor 826 may have a part or all of the above-described logicalfunctions instead of the controller 821. The BB processor 826 may be amemory that stores a communication control program, or a module thatincludes a processor and a related circuit configured to execute theprogram. Updating the program may allow the functions of the BBprocessor 826 to be changed. The module may be a card or a blade that isinserted into a slot of the base station device 820. Alternatively, themodule may also be a chip that is mounted on the card or the blade.Meanwhile, the RF circuit 827 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 810.

The radio communication interface 825 may include the multiple BBprocessors 826, as illustrated in FIG. 23. For example, the multiple BBprocessors 826 may be compatible with multiple frequency bands used bythe eNB 800. The radio communication interface 825 may include themultiple RF circuits 827, as illustrated in FIG. 23. For example, themultiple RF circuits 827 may be compatible with multiple antennaelements. Although FIG. 23 illustrates the example in which the radiocommunication interface 825 includes the multiple BB processors 826 andthe multiple RF circuits 827, the radio communication interface 825 mayalso include a single BB processor 826 or a single RF circuit 827.

In the eNB 800 illustrated in FIG. 23, the control unit 153 (and theinformation acquisition unit 151) described with reference to FIG. 9 maybe implemented in the radio communication interface 825. Alternatively,at least some of these components may also be implemented in thecontroller 821. As an example, the eNB 800 may mount a module includinga part (for example, the BB processor 826) or the entire radiocommunication interface 825 and/or the controller 821, and the controlunit 153 (and the information acquisition unit 151) may be implementedin the module. In this case, the module may store a program (in otherwords, a program causing the processor to execute operations of thecontrol unit 153 (and the information acquisition unit 151)) causing theprocessor to function as the control unit 153 (and the informationacquisition unit 151), and execute the program. As another example, aprogram causing the processor to function as the control unit 153 (andthe information acquisition unit 151) may be installed in the eNB 800,and the radio communication interface 825 (for example, the BB processor826) and/or the controller 821 may execute the program. As describedabove, as a device including the control unit 153 (and the informationacquisition unit 151), the eNB 800, the base station device 820 or themodule may be provided. A program causing the processor to function asthe control unit 153 (and the information acquisition unit 151) may alsobe provided. In addition, a readable recording medium in which theprogram is recorded may be provided.

In addition, in the eNB 800 illustrated in FIG. 23, the radiocommunication unit 120 described with reference to FIG. 10 may beimplemented in the radio communication interface 825 (for example, theRF circuit 827). In addition, the antenna unit 110 may be implemented inthe antenna 810. In addition, the network communication unit 130 may beimplemented in the controller 821 and/or the network interface 823.

(Second Application)

FIG. 24 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which an embodiment of the technology of thepresent disclosure may be applied. An eNB 830 includes one or moreantennas 840, a base station device 850, and an RRH 860. Each antenna840 and the RRH 860 may be connected to each other via an RF cable. Thebase station device 850 and the RRH 860 may be connected to each othervia a high speed line such as an optical fiber cable.

Each of the antennas 840 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the RRH 860 to transmit and receive radio signals. The eNB 830may include the multiple antennas 840, as illustrated in FIG. 24. Forexample, the multiple antennas 840 may be compatible with multiplefrequency bands used by the eNB 830. Although FIG. 24 illustrates theexample in which the eNB 830 includes the multiple antennas 840, the eNB830 may also include a single antenna 840.

The base station device 850 includes a controller 851, a memory 852, anetwork interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 23.

The radio communication interface 855 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and provides radiocommunication to a terminal positioned in a sector corresponding to theRRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 may typically include, for example, a BB processor 856.The BB processor 856 is the same as the BB processor 826 described withreference to FIG. 23, except the BB processor 856 is connected to the RFcircuit 864 of the RRH 860 via the connection interface 857. The radiocommunication interface 855 may include the multiple BB processors 856,as illustrated in FIG. 24. For example, the multiple BB processors 856may be compatible with multiple frequency bands used by the eNB 830.Although FIG. 24 illustrates the example in which the radiocommunication interface 855 includes the multiple BB processors 856, theradio communication interface 855 may also include a single BB processor856.

The connection interface 857 is an interface for connecting the basestation device 850 (radio communication interface 855) to the RRH 860.The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station device 850 (radio communication interface 855) to the RRH860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station device 850. Theconnection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include, for example, the RF circuit 864. The RF circuit 864may include, for example, a mixer, a filter, and an amplifier, andtransmits and receives radio signals via the antenna 840. The radiocommunication interface 863 may include multiple RF circuits 864, asillustrated in FIG. 24. For example, the multiple RF circuits 864 maysupport multiple antenna elements. Although FIG. 24 illustrates theexample in which the radio communication interface 863 includes themultiple RF circuits 864, the radio communication interface 863 may alsoinclude a single RF circuit 864.

In the eNB 830 illustrated in FIG. 24, the control unit 153 (and theinformation acquisition unit 151) described with reference to FIG. 10may be implemented in the radio communication interface 855 and/or theradio communication interface 863. Alternatively, at least some of thesecomponents may also be implemented in the controller 851. As an example,the eNB 830 may mount a module including a part (for example, the BBprocessor 856) or the entire radio communication interface 855 and/orthe controller 851, and the control unit 153 (and the informationacquisition unit 151) may be implemented in the module. In this case,the module may store a program (in other words, a program causing theprocessor to execute operations of the control unit 153 (and theinformation acquisition unit 151)) causing the processor to function asthe control unit 153 (and the information acquisition unit 151), andexecute the program. As another example, a program causing the processorto function as the control unit 153 (and the information acquisitionunit 151) may be installed in the eNB 830, and the radio communicationinterface 855 (for example, the BB processor 856) and/or the controller851 may execute the program. As described above, as a device includingthe control unit 153 (and the information acquisition unit 151), the eNB830, the base station device 850 or the module may be provided. Aprogram causing the processor to function as the control unit 153 (andthe information acquisition unit 151) may also be provided. In addition,a readable recording medium in which the program is recorded may beprovided.

In addition, in the eNB 830 illustrated in FIG. 24, for example, theradio communication unit 120 described with reference to FIG. 10 may beimplemented in the radio communication interface 863 (for example, theRF circuit 864). In addition, the antenna unit 110 may be implemented inthe antenna 840. In addition, the network communication unit 130 may beimplemented in the controller 851 and/or the network interface 853.

<7.2. Applications Related to Terminal Device>

(First Application)

FIG. 25 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which an embodiment of thetechnology of the present disclosure may be applied. The smartphone 900includes a processor 901, a memory 902, a storage 903, an externalconnection interface 904, a camera 906, a sensor 907, a microphone 908,an input device 909, a display device 910, a speaker 911, a radiocommunication interface 912, one or more antenna switches 915, one ormore antennas 916, a bus 917, a battery 918, and an auxiliary controller919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of an application layer and another layerof the smartphone 900. The memory 902 includes RAM and ROM, and stores aprogram that is executed by the processor 901, and data. The storage 903may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 904 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. The sensor 907 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundsthat are input to the smartphone 900 to audio signals. The input device909 includes, for example, a touch sensor configured to detect touchonto a screen of the display device 910, a keypad, a keyboard, a button,or a switch, and receives an operation or an information input from auser. The display device 910 includes a screen such as a liquid crystaldisplay (LCD) and an organic light-emitting diode (OLED) display, anddisplays an output image of the smartphone 900. The speaker 911 convertsaudio signals that are output from the smartphone 900 to sounds.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs radiocommunication. The radio communication interface 912 may typicallyinclude, for example, a BB processor 913 and an RF circuit 914. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 914 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 916.The radio communication interface 912 may also be a one chip module thathas the BB processor 913 and the RF circuit 914 integrated thereon. Theradio communication interface 912 may include the multiple BB processors913 and the multiple RF circuits 914, as illustrated in FIG. 25.Although FIG. 25 illustrates the example in which the radiocommunication interface 912 includes the multiple BB processors 913 andthe multiple RF circuits 914, the radio communication interface 912 mayalso include a single BB processor 913 or a single RF circuit 914.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a radio local areanetwork (LAN) scheme. In that case, the radio communication interface912 may include the BB processor 913 and the RF circuit 914 for eachradio communication scheme.

Each of the antenna switches 915 switches connection destinations of theantennas 916 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 912.

Each of the antennas 916 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the radio communication interface 912 to transmit and receiveradio signals. The smartphone 900 may include the multiple antennas 916,as illustrated in FIG. 25. Although FIG. 25 illustrates the example inwhich the smartphone 900 includes the multiple antennas 916, thesmartphone 900 may also include a single antenna 916.

Furthermore, the smartphone 900 may include the antenna 916 for eachradio communication scheme. In that case, the antenna switches 915 maybe omitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to blocksof the smartphone 900 illustrated in FIG. 25 via feeder lines, which arepartially shown as dashed lines in the figure. The auxiliary controller919 operates a minimum necessary function of the smartphone 900, forexample, in a sleep mode.

In the smartphone 900 illustrated in FIG. 25, the informationacquisition unit 241 and the control unit 243 described with referenceto FIG. 10 may be implemented in the radio communication interface 912.Alternatively, at least some of these components may also be implementedin the processor 901 or the auxiliary controller 919. As an example, thesmartphone 900 may mount a module including a part (for example, the BBprocessor 913) or the entire radio communication interface 912, theprocessor 901 and/or the auxiliary controller 919, and the informationacquisition unit 241 and the control unit 243 may be implemented in themodule. In this case, the module may store a program (in other words, aprogram causing the processor to execute operations of the informationacquisition unit 241 and the control unit 243) causing the processor tofunction as the information acquisition unit 241 and the control unit243, and execute the program. As another example, a program causing theprocessor to function as the information acquisition unit 241 and thecontrol unit 243 may be installed in the smartphone 900, and the radiocommunication interface 912 (for example, the BB processor 913), theprocessor 901 and/or the auxiliary controller 919 may execute theprogram. As described above, as a device including the informationacquisition unit 241 and the control unit 243, the smartphone 900 or themodule may be provided. A program causing the processor to function asthe information acquisition unit 241 and the control unit 243 may alsobe provided.

In addition, in the smartphone 900 illustrated in FIG. 25, for example,the radio communication unit 220 described with reference to FIG. 11 maybe implemented in the radio communication interface 912 (for example,the RF circuit 914). In addition, the antenna unit 210 may beimplemented in the antenna 916.

(Second Application)

FIG. 26 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which an embodiment ofthe technology of the present disclosure may be applied. The carnavigation device 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a radio communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls anavigation function and another function of the car navigation device920. The memory 922 includes RAM and ROM, and stores a program that isexecuted by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure a position (such as latitude, longitude, and altitude) of thecar navigation device 920. The sensor 925 may include a group of sensorssuch as a gyro sensor, a geomagnetic sensor, and an air pressure sensor.The data interface 926 is connected to, for example, an in-vehiclenetwork 941 via a terminal that is not shown, and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 927 reproduces content stored in a storage medium(such as a CD and a DVD) that is inserted into the storage mediuminterface 928. The input device 929 includes, for example, a touchsensor configured to detect touch onto a screen of the display device930, a button, or a switch, and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs sounds of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme such as LET and LTE-Advanced, and performs radiocommunication. The radio communication interface 933 may typicallyinclude, for example, a BB processor 934 and an RF circuit 935. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 935 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 937.The radio communication interface 933 may be a one chip module havingthe BB processor 934 and the RF circuit 935 integrated thereon. Theradio communication interface 933 may include the multiple BB processors934 and the multiple RF circuits 935, as illustrated in FIG. 26.Although FIG. 26 illustrates the example in which the radiocommunication interface 933 includes the multiple BB processors 934 andthe multiple RF circuits 935, the radio communication interface 933 mayalso include a single BB processor 934 or a single RF circuit 935.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a radio LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches connection destinations of theantennas 937 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 933.

Each of the antennas 937 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the radio communication interface 933 to transmit and receiveradio signals. The car navigation device 920 may include the multipleantennas 937, as illustrated in FIG. 26. Although FIG. 26 illustratesthe example in which the car navigation device 920 includes the multipleantennas 937, the car navigation device 920 may also include a singleantenna 937.

Furthermore, the car navigation device 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigation device920.

The battery 938 supplies power to blocks of the car navigation device920 illustrated in FIG. 26 via feeder lines that are partially shown asdashed lines in the figure. The battery 938 accumulates power suppliedform the vehicle.

In the car navigation device 920 illustrated in FIG. 26, the informationacquisition unit 241 and the control unit 243 described with referenceto FIG. 11 may be implemented in the radio communication interface 933.Alternatively, at least some of these components may also be implementedin the processor 921. As an example, the car navigation device 920 maymount a module including a part (for example, the BB processor 934) orthe entire radio communication interface 933 and/or the processor 921,and the information acquisition unit 241 and the control unit 243 may beimplemented in the module. In this case, the module may store a program(in other words, a program causing the processor to execute operationsof the information acquisition unit 241 and the control unit 243)causing the processor to function as the information acquisition unit241 and the control unit 243, and execute the program. As anotherexample, a program causing the processor to function as the informationacquisition unit 241 and the control unit 243 may be installed in thecar navigation device 920, and the radio communication interface 933(for example, the BB processor 934) and/or the processor 921 may executethe program. As described above, as a device including the informationacquisition unit 241 and the control unit 243, the car navigation device920 or the module may be provided. A program causing the processor tofunction as the information acquisition unit 241 and the control unit243 may also be provided.

In addition, in the car navigation device 920 illustrated in FIG. 26,for example, the radio communication unit 220 described with referenceto FIG. 11 may be implemented in the radio communication interface 933(for example, the RF circuit 935). In addition, the antenna unit 210 maybe implemented in the antenna 937.

Embodiments of the technology of the present disclosure may also berealized as an in-vehicle system (or a vehicle) 940 including one ormore blocks of the car navigation device 920, the in-vehicle network941, and a vehicle module 942. That is, as a device including theinformation acquisition unit 241 and the control unit 243, thein-vehicle system (or the vehicle) 940 may be provided. The vehiclemodule 942 generates vehicle data such as vehicle speed, engine speed,and trouble information, and outputs the generated data to thein-vehicle network 941.

8. CONCLUSION

Respective devices and respective processes according to the embodimentsof the present disclosure have been described above with reference toFIGS. 1 to 26.

According to the embodiment of the present disclosure, the base station100 includes the control unit 153 configured to dynamically change theUL/DL configuration of the TDD carrier. The control unit 153 notifiesthe terminal device of the radio resources for D2D communicationappropriate for the UL/DL configuration. The radio resources are theradio resources of at least one uplink subframe of the UL/DLconfiguration.

In addition, according to the embodiment of the present disclosure, theinformation acquisition unit 241 configured to acquire informationindicating the radio resources for D2D communication appropriate for theUL/DL configuration of the TDD carrier that is dynamically changed bythe base station 100 and the control unit 243 configured to control D2Dcommunication using the radio resources are included. The radioresources are radio resources of at least one uplink subframe of theUL/DL configuration.

Accordingly, for example, the terminal device can appropriately performD2D communication under the TDD environment.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

For example, while the first technical features and the second technicalfeatures have been described, the first technical features and thesecond technical features not have to be used in conjunction.

For example, the first technical features may be used without using thesecond technical features.

For example, the second technical features may be used without using thefirst technical features. In this case, the UL/DL configuration of theTDD carrier may not be dynamically changed. As an example, the basestation (the information acquisition unit) may acquire informationindicating the D2D resources appropriate for the UL/DL configuration (itis not dynamically changed). Therefore, the base station (the controlunit) may notify the terminal device of the D2D resources. The D2Dresources may be the radio resources of at least one uplink subframe ofthe UL/DL configuration. Therefore, the second technical features (thatis, any of the second technical features) may be applied to the D2Dresources.

For example, the example in which the communication system is a systemcompliant with LTE, LTE-Advanced, or communication standards conformingthereto has been described, but the present disclosure is not limited tothe example. For example, the communication system may be a systemcompliant with other communication standards.

Also, the processing steps in a process in this specification are notstrictly limited to being executed in a time series following thesequence described in a flowchart. For example, the processing steps ina process may be executed in a sequence that differs from a sequencedescribed herein as a flowchart, and furthermore may be executed inparallel.

In addition, a computer program (in other words, a computer programcausing the processor to execute operations of components of the device)causing the processor (for example, the CPU and the DSP) included indevices (for example, the base station, the base station device for thebase station, or a module for the base station device, or the terminaldevice or the module for the terminal device) of this specification tofunction as components (for example, the information acquisition unitand/or the control unit) of the device can be created. In addition, arecording medium in which the computer program is recorded may beprovided. In addition, a device (for example, a finished product or amodule (for example, a component, a processing circuit or a chip) forthe finished product) including a memory in which the computer programis stored and one or more processors capable of executing the computerprogram may be provided. In addition, a method including operations ofcomponents (for example, the information acquisition unit and/or thecontrol unit) of the device may be included in the embodiments of thetechnology according to the present disclosure.

In addition, the effects described in the present specification aremerely illustrative and demonstrative, and not limitative. In otherwords, the technology according to the present disclosure can exhibitother effects that are evident to those skilled in the art along with orinstead of the effects based on the present specification.

Additionally, the present technology may also be configured as below.

(1)

A device including:

circuitry configured to

dynamically change an uplink/downlink configuration of a time divisionduplex (TDD) carrier, and

notify a terminal device of a radio resource for device-to-devicecommunication for the uplink/downlink configuration,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(2)

The device according to (1), wherein the circuitry is further configuredto change the uplink/downlink configuration from one configuration amongmultiple configurations to another configuration among the multipleconfigurations.

(3)

The device according to (2),

wherein the circuitry is further configured to notify the terminaldevice of the radio resource for device-to-device communication for theother configuration in accordance with the change of the uplink/downlinkconfiguration, and wherein the radio resource for the anotherconfiguration is a radio resource of at least one uplink subframe of theanother configuration.

(4)

The device according to (2), wherein the circuitry is further configuredto notify the terminal device of the radio resource for device-to-devicecommunication for each of the multiple configurations.

(5)

The device according to (4),

wherein the radio resource for each of the multiple configurationsincludes a radio resource for device-to-device communication for eachconfiguration, and

wherein the radio resource for each configuration is a radio resource ofat least one uplink subframe of the configuration.

(6)

The device according to (4), wherein the radio resource for each of themultiple configurations is a radio resource of at least one uplinksubframe common among the multiple configurations.

(7)

The device according to any one of (1) to (5), wherein a number ofuplink subframes included in the at least one uplink subframe differsaccording to a number of uplink subframes of the uplink/downlinkconfiguration.

(8)

The device according to any one of (1) to (7), wherein the radioresource is a periodic radio resource that is repeated at a periodcorresponding to a number of uplink subframes of the uplink/downlinkconfiguration.

(9)

The device according to any one of (1) to (8), wherein the radioresource is a radio resource of an uplink subframe of a first number andis a periodic radio resource that is repeated at a first period when theuplink/downlink configuration is a first configuration, and the radioresource is a radio resource of an uplink subframe of a second numberthat is less than the first number and is a periodic radio resource thatis repeated at a second period shorter than the first period when theuplink/downlink configuration is a second configuration.

(10)

The device according to any one of (1) to (9), wherein the circuitry isfurther configured to notify the terminal device of the radio resourcewhen a number of uplink subframes of the uplink/downlink configurationis equal to or greater than a predetermined number.

(11)

The device according to any one of (1) to (9), wherein theuplink/downlink configuration is a configuration including at least apredetermined number of uplink subframes.

(12)

The device according to any one of (1) to (11),

wherein each of the at least one uplink subframe is included in two ormore successive uplink subframes of the uplink/downlink configuration,and

wherein one or more uplink subframes of the two or more successiveuplink subframes are not included in the at least one uplink subframe.

(13)

The device according to (12), wherein the circuitry is furtherconfigured to notify the terminal device of the radio resource when theuplink/downlink configuration includes two or more successive uplinksubframes.

(14)

The device according to (12), wherein the uplink/downlink configurationis a configuration including two or more successive uplink subframes.

(15)

The device according to any one of (1) to (14), wherein the circuitry isfurther configured to notify the terminal device of the radio resourceby reporting system information indicating the radio resource.

(16)

The device according to any one of (1) to (15), wherein the circuitry isfurther configured to notify control unit notifies the terminal deviceof the uplink/downlink configuration.

(17)

A method including:

dynamically changing, by a processor, an uplink/downlink configurationof a time division duplex (TDD) carrier; and

notifying a terminal device of a radio resource for device-to-devicecommunication for the uplink/downlink configuration,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(18)

A device including:

circuitry configured to

acquire information indicating a radio resource for device-to-devicecommunication for an uplink/downlink configuration of a time divisionduplex (TDD) carrier that is dynamically changed by a base station; and

control device-to-device communication using the radio resource,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(19)

The device according to (18),

wherein the uplink/downlink configuration is a configuration that ischanged from one configuration among multiple configurations to anotherconfiguration among the multiple configurations, and

wherein the circuitry is further configured to acquire informationindicating the radio resource for the uplink/downlink configurationamong radio resources for device-to-device communication appropriate forthe respective multiple configurations on the basis of theuplink/downlink configuration.

(20)

A method including:

acquiring information indicating a radio resource for device-to-devicecommunication for an uplink/downlink configuration of a time divisionduplex (TDD) carrier that is dynamically changed by a base station; and

controlling, by a processor, device-to-device communication using theradio resource, wherein the radio resource is a radio resource of atleast one uplink subframe of the uplink/downlink configuration.

(21)

A program causing a processor to execute:

dynamically changing an uplink/downlink configuration of a time divisionduplex (TDD) carrier; and

notifying a terminal device of a radio resource for device-to-devicecommunication for the uplink/downlink configuration,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(22)

A non-transitory computer-readable recording medium having a programstored thereon, the program causing a processor to execute:

dynamically changing an uplink/downlink configuration of a time divisionduplex (TDD) carrier; and

notifying a terminal device of a radio resource for device-to-devicecommunication appropriate for the uplink/downlink configuration,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(23)

A program causing a processor to execute:

acquiring information indicating a radio resource for device-to-devicecommunication for an uplink/downlink configuration of a time divisionduplex TDD carrier that is dynamically changed by a base station; and

controlling device-to-device communication using the radio resource,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

(24)

A non-transitory computer-readable recording medium having a programstored thereon, the program causing a processor to execute:

acquiring information indicating a radio resource for device-to-devicecommunication for an uplink/downlink configuration of a time divisionduplex TDD carrier that is dynamically changed by a base station; and

controlling device-to-device communication using the radio resource,

wherein the radio resource is a radio resource of at least one uplinksubframe of the uplink/downlink configuration.

REFERENCE SIGNS LIST

-   -   1 communication system    -   100 base station    -   101 cell    -   150 processing unit    -   151 information acquisition unit    -   153 control unit    -   200 terminal device    -   240 processing unit    -   241 information acquisition unit    -   243 control unit

The invention claimed is:
 1. A device comprising: circuitry configuredto dynamically change an uplink/downlink configuration of a timedivision duplex (TDD) carrier, and notify a terminal device of a radioresource for device-to-device communication for the uplink/downlinkconfiguration, wherein the radio resource corresponds to at least oneuplink subframe of the uplink/downlink configuration, each of the atleast one uplink subframe is included in two or more successive uplinksubframes of the uplink/downlink configuration, one or more uplinksubframes of the two or more successive uplink subframes are notincluded in the at least one uplink subframe, and the circuitry isfurther configured to notify the terminal device of the radio resourcewhen the uplink/downlink configuration includes two or more successiveuplink subframes.
 2. The device according to claim 1, wherein thecircuitry is further configured to change the uplink/downlinkconfiguration from one configuration among multiple configurations toanother configuration among the multiple configurations.
 3. The deviceaccording to claim 2, wherein the circuitry is further configured tonotify the terminal device of the radio resource for device-to-devicecommunication for the other configuration in accordance with the changeof the uplink/downlink configuration, and the radio resource appropriatefor the another configuration is a radio resource of at least one uplinksubframe of the other configuration.
 4. The device according to claim 2,wherein the circuitry is further configured to notify the terminaldevice of the radio resource for device-to-device communication for eachof the multiple configurations.
 5. The device according to claim 4,wherein the radio resource for each of the multiple configurationsincludes a radio resource for device-to-device communication for eachconfiguration, and the radio resource for each configuration correspondsto at least one uplink subframe of the configuration.
 6. The deviceaccording to claim 4, wherein the radio resource for each of themultiple configurations corresponds to at least one uplink subframecommon among the multiple configurations.
 7. The device according toclaim 1, wherein a number of uplink subframes included in the at leastone uplink subframe differs according to a number of uplink subframes ofthe uplink/downlink configuration.
 8. The device according to claim 1,wherein the radio resource is repeated at a period corresponding to anumber of uplink subframes of the uplink/downlink configuration.
 9. Thedevice according to claim 1, wherein the circuitry is further configuredto notify terminal device of the radio resource when a number of uplinksubframes of the uplink/downlink configuration is equal to or greaterthan a predetermined number.
 10. The device according to claim 1,wherein the uplink/downlink configuration is a configuration includingat least a predetermined number of uplink subframes.
 11. The deviceaccording to claim 1, wherein the uplink/downlink configuration is aconfiguration including two or more successive uplink subframes.
 12. Thedevice according to claim 1, wherein the circuitry is further configuredto notify the terminal device of the radio resource by reporting systeminformation indicating the radio resource.
 13. The device according toclaim 1, wherein the circuitry is further configured to notify theterminal device of the uplink/downlink configuration.
 14. A devicecomprising: circuitry configured to acquire information indicating aradio resource for device-to-device communication for an uplink/downlinkconfiguration of a time division duple (TDD) carrier dynamically changedby a base station; and control device-to-device communication using theradio resource, wherein the radio resource corresponds to at least oneuplink subframe of the uplink/downlink configuration, theuplink/downlink configuration is a configuration that is changed fromone configuration among multiple configurations to another configurationamong the multiple configurations, and wherein the circuitry is furtherconfigured to acquire information indicating the radio resource for theuplink/downlink configuration among radio resources for device-to-devicecommunication for the respective multiple configurations on the basis ofthe uplink/downlink configuration.
 15. A method comprising: acquiringinformation indicating a radio resource for device-to-devicecommunication for an uplink/downlink configuration of a time divisionduple (TDD) carrier that is dynamically changed by a base station; andcontrolling, by a processor, device-to-device communication using theradio resource, wherein the radio resource corresponds to at least oneuplink subframe of the uplink/downlink configuration, theuplink/downlink configuration is a configuration that is changed fromone configuration among multiple configurations to another configurationamong the multiple configurations, and wherein the method furtherincludes acquiring information indicating the radio resource for theuplink/downlink configuration among radio resources for device-to-devicecommunication for the respective multiple configurations on the basis ofthe uplink/downlink configuration.
 16. A device comprising: circuitryconfigured to dynamically change an uplink/downlink configuration of atime division duplex (TDD) carrier, and notify a terminal device of aradio resource for device-to-device communication for theuplink/downlink configuration, wherein the radio resource is periodicand period information indicating a period of the radio resource isnotified by the circuitry with a configuration of the uplink/downlinkconfiguration of a TDD, and wherein the radio resource corresponds to anuplink subframe of a first number and is repeated at a first period whenthe uplink/downlink configuration is a first configuration, and theradio resource is a radio resource of an uplink subframe of a secondnumber less than the first number and is repeated at a second periodshorter than the first period when the uplink/downlink configuration isa second configuration.